Aim: Based on their anticancer properties, probiotics could be used in combination with conventional colorectal cancer (CRC) therapies. Recent studies showed the ability of probiotics to enhance the apoptosis-induction capacity and reduce several undesirable effects of 5-fluorouracil (5-FU). Here we aimed to evaluate the impact of probiotics on the outcome of CRC in a rat model treated with capecitabine (an oral prodrug of 5-FU). Methods: 30 male Wistar-Lewis rats induced with 1,2-dimethylhydrazine (1,2-DMH) for colorectal carcinogenesis were grouped as follows: only 1,2-DMH (Group A, n = 10), 1,2-DMH + capecitabine (Group B, n = 10), 1,2-DMH + capecitabine + probiotics (Group C, n = 10). Control group (Group D, n = 5). Overall survival (OS) was taken account of to the end of induction until death or humanitarian sacrifice. Infostat statistic system was employed (p <0.001 was considered as significative). Results: At 90 days after the induction and at the end of life, the average weight gain was higher in Group C than D (p = .001). Diarrhea, constipation and blood stool were absent in Group C. Furthermore, the tumor burden was lower in this group than Group B or A (1.25 vs. 1.81 vs. 4.8 cm2, respectively). Group A developed left CRC in 70%, B in 33% and C in 22% of cases. Interestingly, Group B and C showed only mucinous carcinoma while in Group A the tumor types were variable. Metastatic lymph node was observed only in Group A and B. The mean survival of Groups A, B, C and D was 250 (95%IC: 242.5-253.1), 380 (95%IC: 337.8-421.9), 480 (95%IC: 436.9-530.7) and 588 (95%IC: 565.8-609.3) days, respectively (p =.001). Regarding Group A, OS was significantly different from Group B (p =.001) and C (p =.001), conversely to what was observed between Group C and D (p =.012). All rats of Group A died from tumor progression, compared with 44.5% of Group B and C. Conclusions: Our study showed a positive effect of probiotics on weight gain, developing cancer, number, localization and tumor burden, and survival of colorectal cancer in rats treated with capecitabine. Moreover, no adverse effects were observed in the group which had consumed probiotics. These findings should be confirmed in further studies.
18th ECCO - 39th ESMO -33 ESTRO European Cancer Congress, 26-30 Sept, 2014, Madrid, Spain.Abstract # 4562, Poster # 155P